Diffusion-Weighted MR Imaging in the Evaluation of Pancreatic Exocrine Function Before and After Secretin Stimulation

Abstract

To evaluate diffusion weighted MR imaging before and after secretin stimulation in the assessment of pancreatic exocrine function in the setting of chronic pancreatitis. Nine patients with severe chronic pancreatitis and sixteen patients without chronic pancreatitis but with a history of chronic alcohol consumption were enrolled in the chronic pancreatitis and risk groups, respectively. Thirty-eight patients without any pancreatic disease or history of alcohol consumption were included in the control group. Diffusion weighted images were obtained before and after secretin administration in all patients. The peak ADC values and times were determined and intergroup differences were compared. A receiver operating characteristic curve (ROC) was used to identify the cutoff values of the peak ADC times for discrimination of control group from risk and chronic pancreatitis groups. In the control group, a peak increase in ADC value of 57-120% (median: 75%) was observed between 90 s and 4 min (median: 2 min) after administration of secretin (Pattern 1). In the risk group, in 13 patients, a peak increase of 52-150% was observed between 4 and 8 min (median: 7 min; Pattern 2). Peak times were significantly longer in risk group (p < 0.01). In three patients in the risk group, and in all patients in the chronic pancreatitis group, no ADC peak was observed within 10 min following secretin administration (Pattern 3). Using a peak time of 4 min as the cut-off value, a sensitivity of 100% and specificity of 94.7% were achieved in discriminating the control group from the combined risk and chronic pancreatitis groups. Diffusion-weighted MR imaging before and after secretin administration could yield clinically useful information for detecting pathophysiologic alterations in the setting of chronic pancreatitis.